Friction grip device.



No.`788,464. PATENTED APR. 25, 1905.

' B. H. GREEN.

FRIGTION GRIP DEVICE. APPLIOATION FILED nu 16.1904.

O/azwwmd/ /ugh NITED STATES Patented April 25, 1905.

PATENT OFFICE.

FRICTloN GRIP DEVICE.

SPECIFICATION formingpart of Letters Patent No. '788.464, dated April25, 1905.

Application filed May 16, 1904x Serial No. 208,128.

To 1J/Z wiz/0711, t may concern.:

Be it known that I, BUEL H. GREEN, a citizen of the United States,residing at Los Angeles, in the county of Los Angeles and State ofCalifornia, have invented a new and useful Friction Grip Device, ofwhich the following is a specification.

rlhis invention relates to a friction grip device adapted for use as abrake or as a clutch or power-transmitting device, it being particularlyadapted as a brake for motor-vehicles.

One object of the invention is to secure a maximum gripping area with adrum having a minimum diameter.

Another object is to apply the friction-producing strains in such a waythat the stress upon the member being gripped resulting from thepressure of one gripping device is counteracted by an opposite pressureupon the member resulting from the opposing pressure which it receivesfrom the opposite gripping device. g

The accompanying drawings illustrate the invention, and, referringthereto- Figure 1 is a side elevation of the invention with a portion ofthe radius-rod broken away. Fig. 2 is a side elevation of what is shownin Fig. 1, the greater part of the radius-rod being removed. Fig. 3 is asectional view on line m m3, Fig'. 1. Fig. 4 is a sectional view on linem" 51:4, Fig. 3.

1 is a shaft which may be either stationary or rotatable. In the presentembodiment it is shown as a rotatable shaft which passes through an eye2 on the end of a radius-rod 3, which radius-rod may extend to anydesired point of a motor-vehicle frame. (Not shown.)

4 is a drum on the shaft 1. the shell of the drum being provided with anexternal friction-face 5 and an internal friction-face 6.

. lf the shaft 1 is a stationary shaft, the drum 4 may be rotatable onthe shaft. An expanding brake-band 7 is arranged to grip the internalfriction-face 6 of the drum, while a contracting brake-band 8 isarranged to grip the external friction-face 5 of the drum. The

lower ends of the brake-bands 7 and 8 are 'pivotally attached to studs 9and 10, respectilely, which extend laterally from the radiusre 3;

Pivoted at 11 to the free end of the contracting brake-band 8 is one armof a T-lever 12. The other short arm of the T-lever 12 has a stud 13,which-'projects into the drum 4 for a distance about half the width ofthe drum. `The free end 14 of the. expanding brake-band 7 is connectedby a link 15 with the' stud 13.

By pulling forward the lever 12 in the direction of the arrow it will berocked on its pivotal axis 1l, which will move the stud 13 upwardly andthrough the link 15 will expand the brake-band 7. In rocking the lever12 the resistance offered by the expansion of the brake-band 7 movesdown the pivotal point 11 somewhat, so that the brake-band 8 iscontracted. Thus this movement of the lever 12 causes a simultaneousexpansion of the inner brake-band 7 and a contraction of the outerbrake-band 8, and the friction arising between the inner and outersurfaces 5v and 6 of the drum 4 with the brake-bands 7 and 8 results inretarding the rotation of the drum 4 or in stopping it altogether,depending upon the amount of friction.

It will be observed that the strains uponA the drum 4 are equalized andthat a minimum force on the lever 12 will apply the maximum retardingeffect to the drum 4, which would not be the case if the drum 4 wereengaged solely by either the expanding band 7 or the contracting band 8.

As soon as theA pressure on the lever 12 is relieved the natural springof the brake-band 7 contracts it and the brake-band 8 expands for asimilar reason, so that the drum 4 is then free to revolve.

What I claim is- 1. A rotatable member having concave and convexfriction-surfaces, brake-bands for engaging said friction-surfaces, andmeans for simultaneously contracting one brake-band and expanding theother.

2. A drum, brake-bands for engaging the inner and outer surfaces of itsshell and having fixed ends, a lever flexibly connected to the free endof one band, and means connecting the free end of the other band withthe lever whereby when the lever is rocked one band is contracted andthe other expanded.

3. A drum, brake-bands for engaging the inner and outer surfaces of itsshell and having fixed ends, a lever pivoted to the free end of oneband, and a link connecting the free end of the other band with thelever.

4. A drum, brake-bands for engaging' the inner and outer surfaces of itsshell and having fixed ends, a T-lever pivoted to the free end of oneband, a stud on the lever projecting into the drum, and a linkconnecting the stud with the free end of the other band.

. A drum, expanding' and contracting bands

